In 2014, amateur military historian Dan Mackay of Extreme Relic Hunters (ERH) was on the hunt for artifacts in a field near London, England, when he made a remarkable find. Buried next to a World War II-era anti-artillery gun were more than 14,000 individually inscribed, British Army-issued dog tags.

Although ID tags like have been in use since before World War I, most were made out of vulcanized asbestos fiber until 1960. As noted in the Telegraph, the tags Mackay found are believed to be among the first stainless steel ones commissioned by the British Army, and may have been created in anticipation of the introduction of the newer-model tags. It’s likely the army abandoned those plans and never put them into circulation, instead burying them at the site.

It took several trips to fully unearth the cache, which were then painstakingly cleaned and catalogued. That’s when the real fun began. Working with ERH’s lead researcher Katey Mishler, Mackay began the process of investigating the dog tags’ history and tracking down their meant-to-be owners.

It’s been no easy task. According to a post by Mackay on ERH’s website, the tags were created for members of nearly every regiment of the British Army from before World War II to post-War. Needles, meet haystacks. Mackay then began categorizing the tags based on the data listed for each serviceman, which included names, serial numbers, regiment assignments and even religions.

Desperate to find more information about his discovery, Mackay turned to the Royal British Legion for help. Unfortunately, the RBL didn’t have much interest in helping him reunite the tags with their rightful owners. He received similar responses from every regiment of the Army, as well as newspapers and military magazines he contacted.

Unsure what to do next, he began listing the tags on eBay, where he noticed that they would mostly sell (for a very meager amount) to people with the same surnames as the engravings. One day, he received a note from an eBay user claiming that one of the listed tags belonged to his father. Once the identity was confirmed, Mackay mailed it to the man free of charge. The first dog tag had found its way home.

The 37-year-old relic hunter–and near-full-time dog tag returner–kept up the search on his own until a big break came. When research on the Forces War Records website connected him with a surviving World War II veteran named Frederick Henry Bills, he reached out to the man, and got a reply from Bills’ son the very next day. He eventually delivered the dog tag personally, spending the day with Bills and his family and recounting memories from the war.

It’s moments like these that are, by far, the most rewarding for Mackay, Mishler and ERH. As Mackay told HISTORY, “It’s as if [the dog tags] are being finally put in place after 70-odd years of being lost. The joy and excitement people have when we tell them about the tags is amazing. People say it doesn’t seem real, until then, all of a sudden, they get a tag in their hands.”

So far, Mackay has successfully returned eight dog tags to their rightful places, with more waiting to be shipped out. He and Mishler have taken their search public in hopes of finding homes for as many of the 14,000 as they can. More information can be found on the Extreme Relic Hunters Facebook page and their website.